1. Technical Field
The present invention relates to a technology for forwarding an E-mail.
2. Background Arts
An E-mail system has hitherto provided a forward service for forwarding a received E-mail addressed to a predetermined address. For utilizing this service, a user registers beforehand a forward destination address corresponding to a self-receipt address in a mail server.
Then, the mail server, when receiving the E-mail addressed to this receipt address, forwards this E-mail to the aforementioned forward destination. This scheme enabled the user, when changing the E-mail address, to separately use both of addresses before and after the address change and to forward the E-mail to an E-mail address used in home from an E-mail address used in a workplace.
Thus, a forward function and a forward service of the E-mail were convenient. It was, however, difficult to confirm from only address information whether the forward destination address is valid or not. In order to check validity of the forward destination address, there has hitherto been no alternative but to judge whether the forward destination address exists in, e.g., a pre-registered list or not.
Moreover, if an erroneous mail delivery happens when forwarded to an off-office mail address from an in-office Intranet, there might be a case where enterprise confidential information leaks out. The conventional list checking method was hard to prevent the erroneous mail delivery.
Further, if the mail address changes, the method of referring to the already-registered address list was impossible of judging the validity of the mail address. Still further, once the forward destination address was registered, there was a case in which the unjustified forwarding continued even when the address thereafter became ineffective.